Battery level support

[JCKodel]

This pull request will add 2 things:

1. Update the battery level on the tray itself, so it is visible without having to click on the menu (it will show all battery enabled devices, but I just have one to test, so, don't know how this would be when multiple devices shows their levels):

2. A new color option called Battery Level that will set the device lights from green to red, depending on the battery level

[AlexPerathoner]

Are there updates on this?